Dental-tool grinder



Feb. 21, 1928. 1,659,681

W. G. HART DENTAL TOOL GRINDER 4 Filed April 17. 1922 INVENTOR.

JBZL. I

ATTORNEY-3.

Patented Feb. 21, 1928.

UNITED STATES 1 warms. mm,- or safaris-Ln, rumors.

Barman-r001. eniunnn. f

Application filed April 17,1922. Berlal 1T0. 554,006;

My invention relates to miniature grinders of the type used by dentistsin sharpening by them .in the practice of their profession. I Thegrindingwheel which is formed as a' small stoneor from other abrasivematerial, is mounted upon the front end of a shaft which is journalledintermediate its ends in a: bracket so formed that it may beconveniently attached in position'upon any suitable base or support. Theother end of 1 theshaft, projecting rearwardly from the bracket, isadapted to be clamped in the chuckon thelfree end of the flexiblerotatingshaft whichforms apart ofthe equip ment of the dentists oilice.e i A tool rest issecured to the bracket atthe .front sideofthestone,'andtransversely to the axis thereof, inposition to opposeany .,longitudinal oraxial movement ofthe shaft carrying the stone,sothat thestone will rotate ina fixed plane during the grindingfloperatiomandso tend to accurate well as.

uniform grinding of the instruments.

recess for the reception of the projecting forward end of the shaft, sothat such tool rest may be located in immediate proximity to the stone.7

The tool rest is provided with tool positioning guides, constituted asnotches inclined at various angles with relation to the front face ofthe stone, so that the instruments mav be accurately held in positionand supported near their points to permit correct sharpening. It hasbeen found desirable to form the tool positioning guides upon both theupper and lower faces of the m tool rest. so as to meet the conditionsim' posed when reversal of the attachment is required by any limitationsof space, or for other reasons. b

Having in the foregoing outlined the purposes of my invention and itsgeneral nature,

I will now proceed with a specific description of the constructionillustrated in the drawing, and then point out the novel fea- The faceof the tooLrest next to the front sidepyof the stone,is bored out toform a as clamped upon the rear end. of the shaft 0 p upon which thegrinding stone is mounted. thedehcately pointed instruments emplo edFig. 2 is a view in front elevation, showing the grinder in operativeposition. 7

Fig. 3 is a vertical sectional view on the line3-3,Fig. 2, but showingthe shaft in elevation.

In the drawingthe numeral 10 indicates a bracket or frame formed bycasting, press ing, or otherwise, and provided with means,

as a leg 11 and foot 12, for convenient attachment in any desiredangular position upon a fixed or-stationary base or support.

I The front face of the-bracket is formed as a yoke, between the prongs13 of which, space is provided for the accommodation of a small grindingwheel 14. the rear side of which lies in close proximity to the baseplane 15 of the yoke. The thickness of the stone approximates the depthof the yoke.

The rearsideof the bracket is extended to form'a boss 16, which is boredtransversely toform a bearing for a short, revoluble shaft 17.,which mayrotate in a bushing shoulder against which rests 'awasher 19. A threadis out upon the projecting end of the reduced portion of the shaft, anda nut 20 is screwed thereon, to firmly clamp the grinding stone 14against the washer, so that the saidstone will partakeof the rotation ofthe shaft 17 The bushing 18 should extend a short distance beyond thebase 15 1 8,- setin the said bearing. The front end of "the shaft17 isreduced so as to provide s.

of the yoke, as shown in Figs. 1 and 3. so

that'the rotationof the parts will not be impeded by the frictionalengagement of the washer with the bracket.

A tool rest 21, in the form of a bar, extends across the front face ofthe grinding stone, and is secured in position upon the bracket 10 bymeans of screws 22, which pass through the opposite ends of the bar, andare entered into threaded recesses in the prongs 13 of the oke, as shownin Fig. 1. The inner face of the bar in the line of the shaft, isprovided with a circular recess 23, in which is received the front endof the shaft and the clamping nut thereon. The

purpose of this last described feature of construction is to enable thetool rest 21 to be positioned immediately adjacent the outer face of thegrindingstone, so that the space to be bridged by that portion of theimplethe most accurate results will be secured.

The tool rest 21 is speciallyformed so as to adapt it to the successfulperformance of its functions, the said tool rest 21 formed as a barbeing provided upon its upper and lower sides with-a series of notches,some of which are indicated 24:, and which stand at various angles withrelation to the vertical plane of the front face of the grinding wheel.The angular grinding or bevel of the point of the instrument may thus beeffected by selectively positioning the instrument in that notch of thetool rest best adapted for the attainment of the purpose desired.

By providing notches 24, upon both sides of the bar constituting thetool rest, the device is rendered serviceable regardless of whether thefoot 12 be attached at the left or at the right, or in other positionwith relation to the shaft 17. Additional holding guides 25, ofdifferent angles, may be formed upon the cross bar constituting the toolrest, to enlarge the range of the results flowing from the use of thedevice.

The end of the shaft 17 projecting rearwardly of the bracket will bereduced as at 26, to the diameter of the shanks of the drills formingpart of the oflice equipment, so as to be readily entered into andclamped by the chuck 27 upon the free end of the flexible driving shaft28.

In the construction which has been described, the grinding wheel 14 isheld against movement axially of the shaft by which it is carried. By somaintaining the grinding wheel in a fixed plane of rotation, thegrinding of the points of the instruments may be effected with greaterprecision.

Having thus described my invention, what I claim and desire to secure byLetters Patent of the United States, is:

A grinder for dental instruments comprising an attachable bracketrecessed in its face to form a yoke for the reception of a grind-- instone, a short shaft journalledin the said bracket and carrying at itsfront end a. stone arranged within the yoke, the rear end of the shaftprojecting beyond the bracket to permit a driving connection to be madetherewith, in combination with a tool rest secured to the front face ofthe bracket and provided with positioning means for determining theangularity of the points of the instruments with relation to thegrinding stone, the said tool rest being recessed on its inner face forthe reception of the front end of the shaft, whereby the tool rest maybearranged in close proximity to the side face of the stone, and vibrationof the instru ments during the grinding operation be avoided. i 7 v Intestimony whereof, I have si ned my name at Fairfield, Il1inois,this 12tday of April, 1922.

wILLIAM e. Ham

